The invention relates to the electromagnetic interference (EMI) shielding arts. It finds particular application to an enclosure for an electronic assembly where the enclosure includes a waveguide for cables. It will be appreciated that the present invention will find application in any electronic system where shielding of EMI is desired including mainframe computers, network servers and the like.
Electromagnetic interference (EMI) is a common problem faced during the operation of electronic equipment. EMI is unwanted electromagnetic energy entering or emitting from a specific piece of electronic equipment, thereby causing interference. EMI can cause that piece of electronic equipment or electronic equipment nearby to function improperly or to not function at all.
Typically, electronic equipment is housed within a metallic enclosure to help reduce EMI problems. Metallic materials are electrically conductive which serve to block EMI. However, joints or other openings in the enclosure tend to provide a source of radiation leakage and thus cause a reduction in shielding effectiveness. Conventionally, this reduction has been ameliorated by the use of electrically conductive compliant gasket material trapped between the lid or panel and the rest of the enclosure. When the enclosure had cables passing though an opening, a cable shield termination device was required to secure the cable shield to and create an electrically conductive path with the enclosure. In other systems, cables had to pass through a clamp arrangement or other termination device. These types of shield termination devices do not provide much flexibility for configuring and installing EMI enclosures.
Furthermore, when shielding a pre-existing electronic assembly having attached cables, prior art enclosures were difficult to configure to properly shield the electronic device. They often required extensive time and labor for the cables to be disconnected and reconnected to accommodate the enclosure. Further time and labor may be required to modify existing cables to accept devices for terminating the cable shield to the enclosure. If the pre-existing electronic assembly or cables could not be modified, enclosing the assembly required a costly custom made enclosure, if even enclosing the assembly was possible.
The present invention provides a new and useful enclosure that cures the above problems and others.
According to the present invention, an enclosure is provided that includes a housing that reduces electromagnetic interference. A chamber is defined within the housing that receives an electronic assembly having one or more cables connected thereto. A waveguide is formed as a channel within the housing and has two opened ends allowing the one or more cables to extend through. The waveguide has electrically conductive sides and the channel is dimensioned to attenuate radiation having a selected frequency range.
One advantage of the present invention is that shielding an electrical assembly with cables is easily performed.
Still further advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments.